Long term experience of gamma knife radiosurgery for benign skull base meningiomas.

OBJECTIVES: As most reports on the gamma knife have related only to short or mid-term results, we decided to evaluate the effectiveness and toxicity of radiosurgical treatment for benign skull base meningiomas in 200 patients with a follow up of 5-12 years to define the role of gamma knife radiosurgery (GKRS) for basal meningiomas and to provide further data for comparison with other treatment options. METHODS: In total, 99 patients were treated with a combination of microsurgical resection and GKRS. In 101 patients, GKRS was performed as the sole treatment option. Tumour volumes ranged from 0.38 to 89.8 cm3 (median 6.5 cm3), and doses of 7-25 Gy (median 12 Gy) were given to the tumour borders at covering isodose volume curves (range 20-80%, median 45%). RESULTS: The actuarial progression free survival rate was 98.5% at 5 years and 97.2% at 10 years. Passing radiation induced oedema occurred in two patients (1%). The neurological status improved in 83 cases (41.5%), remained unaltered in 108 (54%), and deteriorated in 9 (4.5%). Worsening was transient in seven patients (3.5%) and unrelated to tumour or treatment in one (0.5%). Repeated microsurgical resection was performed in five patients following GKRS (2.5%). CONCLUSIONS: GKRS has proved to be an effective alternative to microsurgical resection, radiotherapy, and Linac based radiosurgery for adjunctive and primary treatment of selected patients with basal meningiomas. Because of the excellent long term tumour control rate and low morbidity associated with GKRS, this treatment option should be used more frequently in the therapeutic management of benign skull base meningiomas.

Intraspinal synovial cyst at the craniocervical junction.

A cystic lesion adjacent to the dens with compression of the lower portion of the medulla oblongata was found on MRI in a 75-year-old male patient with a 2-month history of occipital pain and gait disturbance. Clinically, the patient showed mild tetraparesis, signs of spinal ataxia and symmetrical hyperreflexia. Following subtotal removal of the cyst via left-sided suboccipital craniotomy and left-sided hemilaminectomy of C1 the lesion was classified as synovial cyst on histopathological examination. Postoperatively, the quadriparesis almost completely subsided and the patient is currently doing well, 33 months after surgery. Synovial or ganglion cysts adjacent to the atlantoaxial articulation with ventral compression of the cervicomedullar cord represent rare surgical or radiological entities. Atlantoaxial synovial cysts have no typical radiographic appearance or specific neurological symptoms so that they are frequently misdiagnosed as intraspinal- or skull base tumour, rheumatoid lesion or ectatic vertebral artery. Since no ensuing complications or recurrences have been encountered in cases of incompletely removed cysts the less invasive operative approaches should be used to avoid destabilisation and subsequent additional surgical procedures.

Preservation of cranial nerve function following Gamma Knife radiosurgery for benign skull base meningiomas: experience in 121 patients with follow-up of 5 to 9.8 years.

INTRODUCTION: Microsurgical excision with preservation of juxtaposed neurovascular structures is considered the treatment of choice for skull base meningiomas, but there exists a great controversy regarding surgical resectability, potential risk for subsequent postoperative Cranial Nerve Deficit (CND) and the role of adjuvant or adjunctive treatment options. In this study we evaluated the effect of Gamma Knife Radiosurgery (GKRS) in 121 patients with benign basal meningiomas after a follow-up of 5 to 9.8 years. METHODS: Sixty patients had undergone open resections prior to radiosurgical treatment and 61 patients were treated by GKRS alone. Tumour volumes of 0.5 to 89.9 ccm (median 6.8 ccm) received a median marginal dose of 13 Gy (range 7-25 Gy) at the covering 25% to 80% isodose volume curves (median 45%). RESULTS: Neuroradiological controls demonstrated decreased tumour size in 73 patients (60.3%), stable meningioma volume in 47 cases (38.9%) and tumour enlargement in one patient (0.8%). Clinically, 54 patients (44.6%) improved and 61 cases (50.4%) remained unchanged. Four patients (3.3%) showed temporary and two patients (1.7%) permanent neurological deterioration (unrelated to tumour or treatment in one patient). Two patients (1.7%) developed radiation induced new or aggravated pre-existent CND (1 transient, 1 permanent) and two patients (1.7%) required further surgical resection. CONCLUSION: In our long-term experience, GKRS proved to be an attractive additional and save alternative primary treatment option in selected patients with basal meningiomas. The tumour control rate of 98.3% associated with excellent clinical outcome and low incidence for treatment related CND (1.7%) compares favourably with the reported microsurgical series.

Cranial nerve preservation after radiosurgery of vestibular schwannomas.

Radiosurgery is a management approach used to treat patients with vestibular schwannomas. The goals are long-term tumour growth control, maintenance of cranial nerve function and prevention of new deficiencies. We sought to determine long-term outcomes measuring the potential benefits against the neurological risks of primary radiosurgery. Gamma Knife radiosurgery was applied as a treatment modality for 289 patients with vestibular schwannomas from April 1992 to April 2002. The long-term results of 100 patients who underwent radiosurgery were evaluated. 60 patients received a primary treatment, 40 other cases presented with previously performed subtotal microsurgical resection or recurrence of disease (12-96 months, median 39). The median treatment volume was 3.4 ccm and the median dose to the tumour margin was 13 Gy. The median patient follow-up time was 76 months (range 60-120 months). Four tumours progressed after primary radiosurgery. Tumour control rate was 96%. Useful hearing (Gardner-Robertson I/II) was preserved in 16 patients (55%). Clinical neurological improvement occurred in 50%. Adverse effects comprised neurological symptoms (incomplete facial palsy) (House-Brackman II/III) in six cases (four recovered completely), mild transient trigeminal neuropathy in five cases, and morphological changes displaying rapid enlargement of preexisting macrocysts in two patients and tumour growth in two other patients. Microsurgical resection was performed in four cases (4%) and two patients underwent a shunting procedure because of hydrocephalus formation (2%). In patients who had undergone previous microsurgery, no new cranial nerve deficit was observed. Radiosurgery is an effective method for growth control of vestibular schwannomas and is associated with both a low mortality rate and a good quality of life. Accordingly, for the preservation of cranial nerve function radiosurgery is a useful method for the management of properly selected patients and is comparable to microsurgery.

The role of Gamma Knife radiosurgery in the management of glomus jugular tumours.

BACKGROUND: Glomus jugular tumours are usually managed by microsurgical resection and/or radiotherapy with considerable risk for treatment-related morbidity. The role of Gamma Knife Radiosurgery (GKRS) in the management of these lesions remains to be defined. METHOD: Between May 1992 and November 2000, 19 patients with glomus tumours underwent GKRS at our department. Nine patients received radiosurgery for residual or recurrent paragangliomas following microsurgical resection and in 10 cases GKRS was performed as primary treatment. The median tumour volume was 5.22 ccm (range: 0.38-33.5 ccm). Marginal doses of 12-20 Gy (median 14 Gy) were applied to enveloping isodose volume curves (Range: 30-55%, median 50%). FINDINGS: Except for an 81-year-old patient who died 9 months after radiosurgery the observation time ranged from 1.5 to 10 years (median 7.2 yrs). The total tumour control rate was 94.7% (7 cases with decreased and 11 with stable tumour size). The only patient with tumour progression (5.3%) underwent repeated radiosurgical treatment 85 months after initial GKRS. A newly diagnosed second lesion in the cavernous sinus was treated radiosurgically as well 53 months after the first Gamma Knife procedure. On clinical examination 10 patients (52.6%) presented with improved and 8 patients (42.1%) with unchanged neurological status. Deterioration in one patient (5.3%) was not related to tumour or radiosurgery. INTERPRETATION: As GKRS demonstrated to be a minimally invasive treatment alternative to microsurgery and radiotherapy with no acute or chronic toxicity it should be considered more frequently in the primary or adjuvant strategy for glomus jugular tumours.

Endoscopic percutaneous transforaminal treatment for herniated lumbar discs.

BACKGROUND: The prevailing percutaneous treatment options for herniated non-contained lumbar discs have not reliably achieved the same good results as the conventional microsurgical techniques. In this study we evaluated clinical outcome and complication rate following endoscopic percutaneous transforaminal treatment of extruded or sequestrated herniated lumbar discs in 122 patients with a follow-up period of more than one year. METHOD: Between October 1997 and December 2000, 86 male and 36 female patients with a median age of 55 years (range 18 to 89 years) underwent endoscopic treatment for non-contained herniated lumbar discs at our department. Neurological controls were conducted after 4 to 8 weeks routinely and the clinical result was reassessed at a follow-up of 15 to 53 months (median 35 months) according to the Macnab scale and Prolo outcome score. FINDINGS: On follow-up examination, 96 patients were found with permanently ameliorated or normal clinical status following endoscopy alone. The remaining 26 cases with unchanged or only temporarily improved neurological disorders were submitted to conventional microsurgical interventions. Spinal nerve root injury during endoscopic treatment occurred in two patients but no additional neurological deficits or aggravation of pre-existing disorders were observed. INTERPRETATION: Due to the minimal invasivity, the good functional outcome (78.7% clinical amelioration) and the low complication rate (1.6%), this procedure represents an attractive and efficient treatment alternative especially for foraminal and extraforaminal herniated lumbar discs and reduces the indications for open surgery in selected cases.

Long term results of radiosurgery for vestibular schwannomas.

UNLABELLED: Radiosurgery is either a primary or an adjunct management approach used to treat patients with vestibular schwannomas. The goals are long-term tumour growth control, maintenance of cranial nerve function and prevention of new neurologic deficiencies. We sought to determine long-term outcomes measuring the potential benefits against the neurological risks of radiosurgery. METHODS: 278 patients with vestibular schwannomas underwent Gamma Knife radiosurgery as a treatment modality for from April 1992 to November 2001. The long-term results of 60 patients were evaluated who received radiosurgery as primary treatment. 12 cases presented with previously performed subtotal microsurgical resection or recurrence of disease (12-96 months, median 39). The median treatment volume was 3.8 ccm and the median dose to the tumour margin was 12 Gy. The median patient follow-up time was 88 months (range 72-114 months). RESULTS: Four tumours progressed after primary radiosurgery. Tumour control rate was 93%. Useful hearing (Gardner-Robertson I/II) was preserved in 16 patients (55%). Clinical neurological improvement occurred in 36 patients (60%). Adverse effects comprised neurological symptoms (incomplete facial palsy) (House-Brackman II/III) in five cases (three recovered completely), mild trigeminal neuropathy in three cases, and morphological changes displaying rapid enlargement of preexisting macrocysts in two patients and tumour growth in two other ones. Microsurgical resection was performed in three cases (5%) and one patient underwent a shunting procedure because of hydrocephalus formation. In patients who had undergone previous microsurgery, neither new cranial nerve deficit nor any tumour growth was observed. CONCLUSIONS: Radiosurgery performed with current techniques proved to be an effective method for growth control of vestibular schwannomas with both a low mortality rate and a good quality of life. An increasing percentage of patients will undergo radiosurgery as accessibility to this alternative increases, and more data regarding long-term follow-up are available. It is a post-operative complementary treatment for partially removed tumours. Accordingly, radiosurgery is a useful method for the management of properly selected patients.

Right hemispheric frontal lesions as a cause for anorexia nervosa report of three cases.

OBJECT: Aetiology and pathogenesis of eating disorders is a matter of controversy. In some cases they can occur in association with tumours involving the temporal cortex, in temporal lobe epilepsy or in the advanced state of degenerative diseases involving temporal structures. We report about three patients with right frontal intracerebral lesions, one oligo-astrocytoma and two vascular malformations, associated with partial seizures and anorexia nervosa. PATIENTS AND METHODS: 3 patients, one female and two men with anorexia nervosa and right frontal intracerebral lesions were admitted to our wards due to focal seizures or loss of consciousness. They were treated either microsurgically or by endovascular embolization after neuro-imaging. In our retrospective analysis of the patients' reports and course we investigated the histopathology of the lesions, duration of the eating disorder and the clinical outcome. RESULTS: Two patients underwent craniotomy with extirpation of the lesion. In one case histology revealed an oligo-astrocytoma, in the other haemorrhagic infarction due to a venous malformation. The patient with the arteriovenous malformation (AVM) was embolized with microparticles. The patients with the oligoastrocytoma and AVM totally recovered. They gained weight and stayed seizure free. The patient with the infarction remained in a vegetative state. CONCLUSIONS: Right frontal intracerebral lesions with their close relationship to the limbic system could be causative for eating disorders. We therefore recommend performing a cranial MRI in all patients with suspected eating disorders, especially if they occur in combination with focal seizures.

[Therapy of neurotrophic keratopathy in trigeminal schwannoma with radiosurgery]. / Therapie einer neurotrophen Keratopathie bei Trigeminusschwannom mittels Radiochirurgie.

BACKGROUND: We present a patient with neurotrophic keratopathy due to a trigeminal nerve neurinoma, who was successfully treated by radiosurgery. PATIENT: A patient was referred to us with recurrent corneal erosions of unknown origin in his left eye. In addition, he suffered from mild hypoesthesia in the distribution of the first branch of the trigeminal nerve. He was started on topical lubricants (hyaluronic acid 0.5%) and antibiotic ointments (gentamycin), but since no corneal healing occurred, a soft contact lens was applied. The patient developed severe corneal neovascularization within four weeks and the contact lens had to be removed. Three months later an MRI scan was performed, which showed an intracranial tumor originating from the first branch of the trigeminal nerve. Neurinoma of the trigeminal nerve was suspected, and this presumed diagnosis was confirmed by fine needle biopsy. The patient underwent radiosurgery seven weeks later. The epithelium closed, the cornea recovered and stayed stable until the last examination 18 months after radiosurgery. CONCLUSION: Radiosurgery is a promising alternative to conventional microsurgery in cases of neurinomas of the trigeminal nerve including neurotrophic keratopathy, to keep or restore vision.

Radiosurgery as alternative treatment for skull base meningiomas.

The effect of radiosurgical treatment of skull base meningiomas in 197 patients with a follow-up of at least 2 years was evaluated. Ninety-two of these patients had combined surgical and radiosurgical treatment, while Gamma Knife Radiosurgery (GKRS) was performed as primary treatment in 105 patients. Follow-up was available in 164 patients with intervals of 25-97 months (median 55 months) after GKRS. The imaging controls revealed decreased tumour size in 84 patients (51%), stable tumour volume in 76 ca ses (47%) and increased tumour size in 4 cases (2%). Neurological examinations showed improved neurological status in 58 cases (35%), stable clinical status in 100 patients (61%) and slight worsening in 6 cases (4%). Due to excellent tumour control rate, good clinical outcome and a low complication rate GKRS represents not only an attractive additional treatment option for basal meningiomas, but may even replace microsurgery in selected cases.

The role of gamma knife radiosurgery in children.

OBJECTS: Despite advances in microneurosurgery, the surgical management of deep-seated lesions is still associated with a high risk. Gamma knife radiosurgery (GKRS), however, has improved the outcome of cerebral tumors and arteriovenous malformations (AVMs) in delicate areas. METHODS: Between March 1992 and June 1998, 50 children (age 1-16 years) with intracranial lesions were treated with GKRS. There were 12 low-grade gliomas, 12 high-grade gliomas, 7 craniopharyngiomas, 3 hamartomas, 2 meningiomas of the skull base, 2 vestibular schwannomas, 1 pituitary adenoma, 1 choroid plexus papilloma, and 10 AVMs. The mean size of the pathologies was 4.6 cm3 (range: 0.21-25.5 cm3). A mean marginal dose of 16 Gy (8-25 Gy) was applied to a mean isodose surface of 50% (35-90%). Clinical and neuroradiological follow-up were analyzed for outcome. Follow-up periods of 45 of these patients ranged from 8 to 79 months (mean 36 months); 5 patients were lost to follow-up. Neoplasms decreased in size in 15 cases (41%), remained unchanged in 13 patients (35%), and increased in 9 cases (24%). AVMs obliterated in 3 children (38%) within 24 months. Neurological follow-up demonstrated improved clinical status in 7 patients (15.5%), stable neurological status in 31 cases (69%) and clinical deterioration in 7 patients (15.5%). The treatment was well tolerated and no complications occurred. CONCLUSIONS: GKRS represents a safe and effective treatment option for benign neoplasms or AVMs in pediatric patients and may extend survival times of children with malignant lesions.

Diagnosis and surgical management of intraspinal synovial cysts: report of 19 cases.

OBJECTIVE: Synovial cysts of the vertebral facet joints are a source of nerve root compression. Different surgical procedures are in use, but no consensus has been formed so far as to which method should be used in synovial cysts. To clarify the role of surgical management, the efficacy of operative procedures and factors influencing the outcome in our own series of 19 patients treated between 1994 and 1998 were analysed. METHODS: Nineteen patients with a mean age of 65 years underwent surgery for medically intractable radicular pain or neurological deficits caused by synovial cysts. The patients' records were retrospectively analysed for neurological deficits, cysts diameter, operative approach, segmental hypermobility, and clinical outcome; CT and MRI were analysed for additional degenerative changes. RESULTS: In 17 patients an excellent result and in two patients a good postoperative result was achieved. Twelve patients were found to have hypermobility of the facet joints and six had spondylolisthesis. There was no correlation between cyst diameter, operative approach, and outcome. No intraoperative or postoperative complications occurred. CONCLUSIONS: Age and hypermobility may play a part in the aetiology of facet joint synovial cysts. As all operative strategies showed equally good clinical outcome, total excision via a small flavectomy as the least invasive approach should be considered therapy of choice in patients with cysts causing neurological deficits.

Lumbar disc herniation mimicking meralgia paresthetica: case report.

BACKGROUND: Meralgia paresthetica, a syndrome of pain and/or dysesthesia in the anterolateral thigh, is normally caused by an entrapment of the lateral femoral cutaneous nerve (LFCN) at the anterior superior iliac spine. In a few cases compression of the nerve in the retroperitoneum has been reported to mimic meralgia paresthetica. CASE DESCRIPTION: A 67-year-old woman presented with a 5-year history of permanent paresthesia in the anterolateral thigh. Motor weakness was not detected. Electromyography showed a neurogenic lesion at the level of L3. Lumbar spine MRI detected a foraminal-extraforaminal disc herniation at L2/L3, which was extirpated via a lateral transmuscular approach. The patient was free of symptoms on the first postoperative day. CONCLUSION: In patients with meralgia paresthetica we emphasize a complete radiological investigation of the lumbar spine, including MRI, to exclude radicular compression by a disc herniation or a tumour at the level of L2 or L3.

Staged radiosurgical treatment for large benign cerebral lesions.

OBJECT: Large brain lesions are considered unamenable to gamma knife treatment because of possible adverse effects. The proximity of eloquent brain to a target location, including some arteriovenous malformations (AVMs), still poses a challenge to the neurosurgeon. Because meningiomas and AVMs often show a slow or absent growth rate, partial radiosurgical treatment in cases with risk of unacceptable surgery-related morbidity is an alternative. The authors evaluated the results of staged treatment. METHODS: Since April 1992, 12 patients suffering from large benign tumors (meningiomas) and seven with AVMs considered inoperable underwent gamma knife radiosurgery in staged procedures. All patients with tumors underwent primary open surgery for partial removal of recurrent growth and subsequent radiosurgical treatment. Four men and eight women ranging in age from 26 to 73 years harbored tumors that ranged in volume from 19 to 90 cm3. Marginal dose ranged from 10 to 25 Gy prescribed in the 30 to 50% isodose. The time interval between the radiosurgical treatments varied from 1 to 8 months. Follow up ranged from 5 and 89 months. Three female and four male patients (age range 10-48 years) had undergone previous AVM embolization and were treated with margin doses of 18 to 22 Gy in the 40 to 50% isodose. The volume range of these AVMs was 11 to 25 cm3. The time interval between radiosurgical treatments ranged from 5 to 36 months. The mean follow up was 22.6 months. Neurological follow-up examinations showed clinical improvement in 11 patients (58%), whereas five (26%) remained unchanged. Among tumor patients no deterioration or further tumor growth was observed. Tumor necrosis demonstrated noticed in five patients (26%). One patient with an AVM suffered from seizures and hemiparesis. Follow-up magnetic resonance imaging of the residual nidus disclosed no rebleeding. CONCLUSIONS: For selected patients with large benign lesions staged gamma knife radiosurgery could be an alternative, as evidenced by the authors' series in which there was no mortality and low incidence morbidity.

Gamma Knife radiosurgery of the glomus jugulare tumour - early multicentre experience.

Leksell Gamma Knife was used to treat 66 patients with glomus jugulare tumour at 6 European sites between 1992-1998. The age of the patients ranged between 18-80 years (median 54 years). Gamma Knife radiosurgery was a primary treatment in 30 patients (45. 5%). Open surgery preceded radiosurgery in 24 patients (36.4%), embolisation in 14 patients (21.2%) and fractionated radiotherapy in 5 patients (7.6%). The volume of the tumour ranged 0.5-27 cm(3) (median 5,7 cm(3)). The minimal dose to the tumour margin ranged between 10-30 Gy (median 16.5 Gy). After radiosurgery 52 patients were followed, the follow up period was 3-70 months (median 24 months). Neurological deficit improved in 15 patients (29%) and deteriorated in 3 patients (5,8%), one transient and two persistant. Neuroradiological follow up using MRI or CT was performed in 47 patients 4-70 months (median 24 months) after radiosurgery. Tumour size decreased in 19 patients (40%) while in the remaining 28 patients (60%) no change in the tumour volume was observed. None of the tumours increased in volume during the observation period. Control angiography was performed in 6 patients. Pathological vascularisation completely disappeared in one patient, reduced in two and there was no change in the remaining three. Radiosurgery proves to be a safe treatment for glomus jugulare tumour with no mortality and no acute morbidity. Because of its naturally slow growth rate, up to 10 years of follow up will be necessary to establish a cure rate after radiosurgery for these lesions.

Gamma knife radiosurgery for glomus jugulare tumours.

The aim of this clinical study was to determine the tumour control rate, clinical outcome and complication rate following gamma knife treatment for glomus jugulare tumours. Between May 1992 and May 1998, 13 patients with glomus tumours underwent stereotactic radiosurgical treatment in our department. The age of these patients ranged from 21 to 80 years. The male:female ratio was 2:11. Six patients had primary open surgery for partial removal or recurrent growth and subsequent radiosurgical therapy. Radiosurgery was performed as primary treatment in 7 cases. The median tumour volume was 6.4 cm3 (range: 4.6-13.7 cm3). The median marginal dose applied to an average isodose volume of 50% (30-50%) was 13.5 Gy (12-20 Gy). In 10 patients, a total of 48 MRI and CT follow-up scans were available. The remaining three patients have been excluded from the postradiosurgical evaluation since the observation time (t < 12 months) was too short or patients were lost to follow up. The median interval from Gamma Knife treatment to the last radiological follow-up was 37.6 months (5-68 months). In 4 patients (40%) decreased tumour volumes were observed and in 6 cases (60%) the tumour size remained unchanged. Neurological follow-up examinations revealed improved clinical status in 5 patients (50%), a stable neurological status in 5 patients (50%) and no complications occurred. According to our preliminary experience Gamma Knife radiosurgery represents an effective treatment option for glomus jugulare tumours.

[Radiosurgery of acoustic neurinoma as a minimally invasive alternative to microsurgery]. / Die Radiochirurgie des Akustikusneurinoms als minimal-invasive Alternative zur Mikrochirurgie.

From April 1992 to July 1998 stereotactic radiosurgery (Gamma Knife) was used to treat 1382 patients; 181 had acoustic neurinomas and were followed up, 44 of them for at least 4 years (48-75 months, median 60). With no mortality control of growth tumor was achieved in all cases but one. It was possible to preserve useful hearing in more than half of the patients (60%). In two patients complications due to the radiation with enlargement of the cystic component were observed. One patient needed additional microsurgical decompression. Three patients suffered transient incomplete facial palsy (one permanent, HBI III), and two patients complained of mild trigeminal neuropathy. One suffered from hydrocephalus and a shunting procedure was necessary. The neurological state improved in 23 patients (52%); five complained of new or worsened deficits. Radiosurgery is an effective alternative treatment for acoustic neurinomas with exceptionally low mortality and morbidity. With respect to preserving cranial nerve function the results are just as good as those of microsurgical resection. Short duration of hospitalization and quick return to normal activities make radiosurgery quite cost effective.

Radiosurgery of vestibular schwannomas: a minimally invasive alternative to microsurgery.

From April 1992 till December 1998 stereotactic radiosurgery (Gamma Knife) was applied to 192 patients with vestibular schwannomas. 56 of them had radiosurgery as primary treatment modality and were followed-up for at least 4 years (48-80 months, median 62). Without fatal complications, control of tumour growth was achieved in all but three cases, useful hearing being preserved in more than one half of the patients (62%). The neurological state improved in 30 patients (54%). Irradiation-associated adverse effects (18%) comprised neurological signs (incomplete facial palsy, four cases (two recovered completely), and mild trigeminal neuropathy, three cases, respectively) and morphological changes (three patients) marked by an enlargement of pre-existing cystic components calling for additional surgical treatment: Microsurgical decompression was performed in two cases, the third patient underwent a shunting procedure because of hydrocephalus formation. Based on the present data, radiosurgery represents an effective treatment for vestibular schwannomas associated with an exceptionally low mortality rate and a good quality of life. With respect to the preservation of cranial nerve function, results are comparable to microsurgical resection. A short duration of hospitalization and a quick return to normal activities constitute further advantages and contribute to cost effectiveness in public health care.

Radiosurgery of glomus tumors: midterm results.

Glomus tumors (GT) of the skull-base present a complex surgical challenge due to their delicate localization and specific vascular supply. This study is designed to evaluate the role of stereotactic radiosurgery in the treatment of GT. Thirteen patients with GT have been treated with the Gamma Knife. Radiosurgery was performed because of recurrences after surgical removal in six patients. Histology was not available in seven patients, thus, diagnosis was made from neuroradiological features only. Two of them had partial embolization before Gamma Knife treatment. Clinical and morphological data were collected from 11 patients, who had a representative follow-up of at least 12 months. Mean follow-up was 42 months (range 14 to 72 months). Within the follow-up period there was no tumor progression and no clinical deterioration in any of the patients. 64% of the patients had an improvement of their symptoms, and in 36% the volume of the lesion decreased in size. There was no radiation-related morbidity. It is suggested that radiosurgery seems to be safe and effective in the treatment of GT.